Capacitance sensing systems can sense electrical signals generated on electrodes that reflect changes in capacitance. Such changes in capacitance can indicate a touch event (e.g., the proximity of an object to particular electrodes). Capacitive sense elements may be used to replace mechanical buttons, knobs and other similar mechanical user interface controls. The use of a capacitive sense element allows for the elimination of complicated mechanical switches and buttons, providing reliable operation under harsh conditions. In addition, capacitive sense elements are widely used in modern customer applications, providing new user interface options in existing products. Capacitive sense elements can range from a single button to a large number arranged in the form of a capacitive sense array for a touch-sensing surface. In other cases, capacitive sense elements may be configured to detect capacitance change caused by features of a fingerprint.
Fingerprint or other biometric information may be used to gate access to a variety of functions and applications. The same sensors may be configured to use information that is gathered for biometric security for other, non-secure functions, such as pressure detection and navigation.